A:swimming pool
B:movie theater
C:park
据图回答下列问题.
同学们一定在树上、田间或草丛里见过下图中的小动物吧?其中属于昆虫的是( )
Tim Cook called his mother every week even while he_______ around the world.
一组数据有30个数,把它们分成四组,其中第一组,第二组的频数分别为7,9,第三组的频率为0.1,则第四组的频数是多少?